Yarn windup apparatus



6 Sheets-Sheet 1 Filed March 24, 1965 INVENTOR RICHARD HOWARD COLLINS f A 4% ATTORNEY 29, 1967 R. H. COLLINS 3,338,529

YARN WINDUP APPARATUS Filed March 24, 1965 6 Sheets-Sheet 2 w l9v 7/Tl I "V'v' f 26' F 25 LL W W1 d w I I I41 1'1 H H 26 '1 I I115 r I I l l 1 I I H 26 I U I] 1' I 1 I040" J 11 if 25 s 15 m r n 28 43 I L 45 l TC" I L W; 31

: i- INVENTOR 52 RICHARD HOWARD COLLINS Aug .29, 1967 R. H. COLLINS YARN wmnur APPARATUS Filed March 24, 1965 6 Sheets-Sheet :3

INVENTOR RICHARD HOWARD COLLINS I ATTORNEY g- 29, 1967 R. H. COLLINS 9 YARN WINDUP APPARATUS Filed March 24, 1965 6 Sheets-Sheet 4;

INVENTOR RICHARD HOWARD COLLINS ATTORNEY Aug. 29, 1967 Filed March 24, 1965 R. H. COLLINS YARN WINDUP APPARATUS 6 Sheets-Sheet 5 RICHARD HOWARD COLLINS ATTORNEY Aug. 29, 1967 Filed March 24, 1965 FIG. '8

R. H. COLLINS YARN WINDUP APPARATUS 6 Sheets-$heet 6 INVENTOR RICHARD HOWARD COLLINS ATTORNEY United States Patent Ofiice 3,338,529 Patented Aug. 29, 1967 3,338,529 YARN WINDUP APPARATUS Richard Howard Collins, Wilmington, Del., assignor to E. I. du Pont de Nemours and Company, Wilmington, Del., a corporation of Delaware Filed Mar. 24, 1965, Ser. No. 442,250 3 Claims. (Cl. 24243.1)

ABSTRACT OF THE DISCLOSURE A yarn windup apparatus which forms a yarn package having tapered ends by means of a control mechanism cooperating with a yarn traverse guide means to gradually shorten the length of the traverse guide movement as the radial dimension of the yarn package being formed, increases; the control mechanism having two spaced electrical switch units connected to actuate the yarn traverse guide means and mounted for relative movement relative to each other, a reciprocating element alternately actuating each switch to reciprocate the guide means, and a linkage which decreases the distance between the switch units in accordance with the increasing radial dimension of the yarn package being Wound.

This invention generally relates to the field of controlled windup of filaments or yarns. More specifically the invention involves an improved windup apparatus for use with textile yarns, which apparatus is capable of winding special contour stable yarn packages, such as those with a double taper, at high speeds on cylindrical tube elements of the type adapted for use with surface drive rolls.

It is an object of this invention to provide such an improved tapered package windup apparatus which comprises a traverse mechanism which is reciprocated by electrical means and is automatically restored to full length stroke (or starting length stroke) at the beginning of a winding cycle, even if the preceding cycle was interrupted before the tapered package then being wound was completed.

It is another object of the invention to provide such an improved apparatus comprising a traverse mechanism which does not require a manual resetting to starting position, and which is capable of winding a plurality of tapered packages simultaneously each with a constant predetermined helix angle.

It is another object of this invention to provide such an improved windup apparatus which comprises at least one swing arm for carrying yarn packages during windup, and a power operated means cooperating with each swing arm to selectively positively move said swing arms to the doifing position.

It is a further object to provide such an apparatus which is simple in construction, easy to adjust and repair, yet

effective and reliable in operation.

Other objects and advantages will appear from a consideration of the following specification and claims taken in conjunction with the accompanying drawings in which:

FIGURE 1 is an enlarged end elevational view of a windup apparatus embodying features of the present invention, which shows the drive roll and a pair of empty bobbins mounted on swing-arms; this view shows only a portion of a thread traversing mechanism.

FIGURE 2 is a cross-section taken along line 22 of FIGURE 1 which shows the swing arm mounting and drive mechanism.

FIGURE 3 is an end elevational view, partly in crosssection, of the thread traversing mechanism (this view taken in the same direction as FIGURE 1).

FIGURE 4 is a side elevational view, in cross-section taken along line 4-4 of FIGURE 3, of the traverse mechanism showing cams and electrical switches.

FIGURE 5 is a plan view, in cross-section taken along line 5-5 of FIGURE 4, of the traverse mechanism showing a thread guide and a belt drive.

FIGURE 6 is a cross-section, taken along line 6-6 of FIGURE 1, showing a bobbin and a bobbin chuck.

FIGURE 7 is a partial cross-section, taken along line 77 of FIGURE 1, showing the bobbin drive roll and part of the drive roll motor.

FIGURE 8 is a partial general overall isometric view of a windup apparatus embodying the present invention to give a general idea of the arrangement of major components.

FIGURE 9 is an end view, taken at line 99 of the bobbin and chuck unit shown in FIGURE 6.

FIGURE 10 is an end view, taken at line 1010, of the bobbin and chuck unit of FIGURE 6.

Referring to FIGURES 1, 2 and 8, the principal parts of the windup assembly are mounted on a vertical plate 1 which is secured to a machine frame (not shown). Extending through the plate 1 is the end bell 2 of a synchronous type motor 3; the shaft 4 of the motor 3 carries a drive roll 5. As may be seen in FIGURE 7, the drive roll 5 has an internal web 6 with a tapered bore which matches the tapered portion of the shaft 4; this shaft 4 is carried by ball bearings 7, 8 which are mounted in suitable recesses inside the motor end bell 2. Machine screws 9 secure the motor, end bell, and drive roll assembly to the plate 1.

In FIGURES 1 and 2, a cast housing 10 is secured to the rear face of the plate 1 by a plurality of machine screws 11; the principal function of the housing is to support the upper swing arm shaft 12 and the lower swing arm shaft 13. As may be seen in FIGURE 2, the housing 10 is bored to receive anti-friction bearings which carry the shafts 12, 13; the housing is also provided with a web which joins the principal parts of the housing together. The web 10a carries a flange 1% on its underside; mounted on the opposite faces of the flange 10b are air cylinders 14 and 15 the function of which will be described, below. On the front or exposed ends of the shafts 12 and 13 are upper and lower swing arms 16 and 17, respectively, which are secured to the shafts.

At their front or outer ends, each of the swing arms carry a chuck assembly 18 upon which is mounted a tube 19 upon which a filament or yarn is to be wound. The chuck is shown in detail in FIGURE 6, FIGURE 9, FIG- URE 10 and is comprised of a shaft 20, a pair of anti-friction bearings 21 on the shaft and a generally tubular member 22 mounted for rotation on the outer races of the bearings. One end of the shaft 20 is clamped securely within a suitable bore in the outer end of the swing arm 16 and the swing arm 17. The tubular member 22 is provided with a plurality of thin ribbon-form springs 24 each of which is curved slightly and is contained in a machined recess in the tubular member 22; the curved portion of the spring extends outwardly, beyond the periphery of the tubular member 22, but permits the paper tube 19 to be donned and dotted readily. When the chuck 18 is rotated, centrifugal force urges the springs against the inside of the paper tube 19 to secure the same in position on the chuck.

Refer-ring again to FIGURE 1, the chucks 18, carrying tubes 19, on the swing arm 16 and the swing arm 17 follow a curved path, swinging through an angle of about 10 degrees to 15 degrees. At the rear, each of the swing arm shafts is provided with an arm 25 to which is sedriving contact with the powered drive roll 5. At about the center of each of the swing arm shafts, between the bearings, is an arm 26; at a radius of about 2 inches, each of the arms is in proximity, respectively, to the rod end of one of the air cylinders 14 and 15. In FIGURE 2, it may be seen that the rod end 15a of the cylinder 15 is spaced about A inch away from one side of the arm 26' on the shaft 13; on the rod end 14a of the cylinder 14 is a fixed flange 14b one face of which is spaced about inch away from one side of the arm 26 on the shaft 12. Thus, the swing arms 16 and 17 are not operatively connected to the air cylinders 14, 15 except as described below. The air cylinders are conventional, of the single acting, spring return type, i.e., the piston and rod of a cylinder may be driven by air under pressure in a single direction being returned, when the air is off, by a built-in spring (not shown). The cylinder 14 on the upper swing arm 16 is driven by air applied to the rod end of the cylinder (and has its spring in the head end) while the cylinder 15 on the lower swing arm 17 is driven by air applied to the head end of the cylinder (and has its spring in the rod end). During a winding cycle, the air is normally off (the condition shown in FIGURE 2); therefore, the cylinders 14, 15 at this stage have no effect on the chucks 18 and paper tubes 19.

During the course of winding, the swing arms 16, 17 simultaneously move counterclockwise. as shown in FIGURE 1, thus moving the arm 26 of shaft 13 farther away from the rod end 15a and moving the arm 26 of shaft 12 farther away from the face of the flange 14b. At the time of doffing, however, air is turned on and the rods of the cylinders move into driving engagement with the arms 26 whereupon the swing arms and chucks are driven counterclockwise to their outermost limits or doffing positions at which position a narrow /2 inch) cylindrical band on the chuck tubular member 22, near the swing arms, is brought to bear forcibly against stationary brake shoes 27 which are secured to the plate 1, in order to stop rotation of the chucks and their yarn packages.

In FIGURES 1 and 8 two filaments 30, one for each paper tube 19, extend from a stationary guide G above the windup through a groove in a traversing guide 31 and thence around the lower portion of the drive roll 5. The guide 31 is adapted to be reciprocated in a horizontal plane, in a slot 38 in housing 33 parallel to the axis of the drive roll, by a traversing mechanism 32, to be described. The traversing mechanism 32, shown in FIGURES 3, 4 and 5, is contained within a housing 33 which, at its rear end, is provided with ears to facilitate bolting the assembly to the face of the plate 1. In general, the traversing mechanism is of a type which may be operated at a constant stroke length or in a continuously variable (diminishing) stroke length.

Referring to FIGURES 3, 5, a small block 34 is provided with a ball bearing 35 which surrounds an elongated cylindrical rod 36; the rod 36 is supported at its ends by the housing 33. Secured to the block 34 is a projecting bar 37 which engages a slot 38 in the front wall of the housing 33. Thus, the block 34 is adapted to move in a straight line path being constrained by the rod 36 and the slot 38. Along its exposed face (i.e., outside the housing 33), the bar 37 carries a small ceramic type, generally triangular yarn or filament guide 31 which has a vertical slot 31a at the apex of the triangle which is adapted to engage the filament 30. Rearward of the block 34 and fastened to it is a flexible toothed endless belt 39 which is looped about a pair of pulleys 40, 41 the axes of which are vertical. One pulley 40 is an idler and is rotatably mounted on the interior of housing 33 while the other pulley 41 is mounted on the shaft of a motor 42 which is flange-mounted on the top of the housing 33 as shown. The motor 42 is a conventional alternating current, two phase type which may be reversed by changing the polarity of one of the two phases; the motor is thus 4 adapted to drive the pulley 41, and the belt 39 alternately in opposite directions to reciprocate guide element 31 in slot 38. The motor is alternately switched between the two modes of operation by a mechanism and circuits to be described.

Referring to FIGURES 3, 4, near the bottom of the housing 33 is a long shaft 43 which is rotatably carried in anti-friction hearings in the end walls of the housing; at its rear end the shaft 43 extends completely through the housing 33 and through the plate 1 and carries a cam gear 45 the function of which will be described. Between the bearings, the shaft 43 carries a pair of barrel cams 44 having grooves 44a of opposite hand; in this case the grooves 44a are generally helical, though other shapes could be used. Directly above the shaft 43 and parallel to it is a pair of rods 46 upon which are mounted a pair of slidable blocks 47; on the underside of each of the blocks is a roller 48 which fits closely between the side walls of the cam groove 44a. By rotating the shaft 43 and the cam 44, the blocks 47 may be caused to slide along the rods 46 toward or away from each other depending on the sense of rotation of the shaft and earns. Also mounted on the rods 46, beyond the point of maximum stroke of the blocks 47, as defined by the cam grooves, is a pair of fixed position blocks 49.

On the top face of each of the four blocks 47, 49 is a conventional electrical switch 50 known as a reed switch type which comprises a glass tube within which is a pair of spaced electrodes one of which is attractable magnetically. The electrodes extend out through the respective ends of the glass tube for connection to external circuits( not shown); the tube is sealed and may be filled with an inert gas to prevent oxidation of the electrodes. The electrodes inside the tube may be brought into electrically conductive contact by the presence of a siutable external magnetic field; such a field is provided by a permanent magnet 51 which is mounted on the underside of the black 34. Referring to FIGURE 4, the electrodes of the two reed switches 50 at the left are connected in parallel with each other and the two at the right are connected independently of the two at the left but also in parallel with each other. Flexible conductors (not shown) are used so as to permit the two movable switches to be moved.

Each of the two pairs of parallel-connected switches are connected through a source of electrical power to opposite solenoids of a conventional double pole, double throw latching relay (not shown). In this type relay, the armature and hence the first set of contacts once having been pulled into engagement by energization of a first solenoid remain mechanically latched in that condition (regardless of whether electrical energy is continuously supplied to the first solenoid or not) until a second solenoid on the opposite side of the relay is energized (and the first solenoid is de-energized) whereupon the latch is withdrawn and the armature is spring-driven to a second position where a second set of contacts is engaged and where the armature remains until the first solenoid is energized once again. The above-described opposed sets of relay contacts are each connected to supply power of opposite phase alternately to produce right and left-hand sense of rotation of the motor 42 depending on which phase is connected. Thus, the motor 42 and belt 39 are caused to reverse direction, causing the block 34 and filament guide 31 to be reciprocated or traversed; the length of the stroke will be a function of the spacing of the two inner sets of reed switches 50 which, as described above, may be varied according to the angular position of the shaft 43 and cams 44. If the cams are rotated counterclockwise, as shown in FIGURE 3, then the stroke of the guide will become progressively smaller.

The angular position of the shaft 43 is determined by a gear train which is operatively connected to the lower swing arm 17 and its shaft 13. Referring primarily to FIGURES l and 2 (portions of this mechanism appear also in FIGURES 3, 4, a sector of a'gear 28 is secured to the lower swing-arm shaft 13; the toothed portion of the gear 28 engages an idler gear 52 which is pinned to an idler shaft 53 for rotation therewith (in anti-friction bearings shown in FIGURE 4). In abutment with the idler gear 52 is a driver gear 54, also pinned to the idler shaft 53, the teeth of which driver gear 54 are engaged with the teeth of the cam gear 45 located on the shaft 43. Thus, it' may be seen that motion of the swing arm 17, whether caused by build-up of successive layers of filament on the tube 19 or by manual manipulation by an operator, will cause the gear train to be rotated thus causing the cam shaft 43 to be rotated and having the effect of altering thestroke of the traverse mechanism. Movement of the tube 19 and the arm 17 away from the drive roll will cause counterclockwise rotation of the cams 44, thus causing progressive shortening of the traverse stroke. The driver gear 54 and the cam gear 45 are adapted to be changed readily so as to. provide different drive ratios thus permitting changes to be made in the rate of change of the traverse stroke for a given increment of angular displacement of the swing arm.

Referring particularly to FIGURE 1, the rotary drive roll 5 is brought up to a desired surface speed by energizing the motor 3; empty tubes 19 are placed on each of the chucks 18 and the tubes are accelerated by surface contact with the rotating drive roll. The traverse mechanism is energized by applying power to the motor 42. Filaments 30 or yarns from a source located generally above the windup but not shown (e.g., an extrusion device or a spinneret) are advanced downwardly as shown in FIGURE 1. The filaments descend in near proximity to the reciprocating traversing guide 31 and the drive roll 5; at this stage one of the filaments may be handled conveniently by an air aspirated suction device (not shown) of the general type taught by Miller in US. Patent 2,667,- 964 which is adapted to take filaments up at high velocities and, by manual manipulation, to string-up the filaments to a winding apparatus such as that described herein. The running filament is manually carried, by such a suction device, down past the traversing guide 31 and clockwise for about 130 around the drive roll 5; as the filament is brought within the limits of the stroke of the traversing guide 31, it is automatically picked up in the slot 31a being cammed into place by the sloping sides (FIGURE 5) of the guide 31. As soon as the filament engages the slot 31a, it, of course, is traversed and will be laid down in a generally helical path on the surface of the drive roll.

Returning to the suction device, further manual manipulation of the device brings the filament, in a counterclockwise direction, fully about the empty tube 19 on lower arm 17. The filament wraps about the tube in such a fashion that it crosses over and binds a preceding wrap; since the tube 19 is power-driven from the drive roll 5, tension downstream of the tube rises abruptly, resulting in breakage of the filament between the tube and the suction device. The oncoming or leading end of the filament is now being taken up on the tube 19 while the trailing end disappears into the suction device. The filament proceeds to wind, being deposited on the tube from its generally helical disposition on the drive roll; at the completion of a traverse stroke, the guide 31 reverses direction and the resulting increase in the radial thickness of the filaments on the tube causes the swing arm to move in a counterclockwise direction about its shaft, thus effecting a decrease in the traverse stroke in the manner described above. Immediately after stringing up the first filament on the tube of the lower arm, the other filament is strung up on the tube 19 of the upper arm 16 for substantially simultaneous wind-up. Obviously, successive layers of filament will be deposited at progressively shorter traverse strokes so that the ends of the packages being wound will appear conical. The cone included angle will be a function of the gear ratio of gears 54 to 45 as well as the shape of the switch cams. The change gears, mentioned above, permit winding at included angles of 24 to 34 degrees.

The helix angle at which the filaments are wound on the drive roll and thence on the packages is a function solely of the velocity of the traverse guide related to the longitudinal velocity of the filaments; if the velocity of traverse is increased, then the helix angle on the wound packages will increase, i.e., the axial spacing between successive wraps on the package will increase, the helix angle being the angle between the filament, as it lies on the package, and a plane at right angles to the package axis of rotation. This windup is designed for a range of helix angles which will. result in filament spacings in the order of two to ten filament diameters; this may be accomplished by providing a conventional manually adjustable device (not shown) for varying the speed of the traverse motor 42 independently of the speed of the drive roll motor.

In the description of the switches, above, it was mentioned that provision was made for stationary switch blocks 49 outside the limits of travel of the moving switch blocks 47. The purpose of these is twofold: (1) as a safety device in case of failure of the movable switches, and (2) to permit manual manipulation of the swing arms at any point in a winding cycle without the necessity for resetting switches, etc. For example, a malfunction upstream of the windup apparatus may require the operator to stop winding and to doif the incomplete package. If

this is done with electrical power to the windup on there will be no problem; if, however, the power fails or is deliberately turned off, then the latching relay which controls the traverse motor 42 will remain in the position in which it was last situated, thus, if power is restored, the motor will continue to run in the same direction in which it was formerly running. Upon resumption of operations, then, the first traverse stroke could exceed that for which the mechanism was designed thus resulting in damage to the mechanism; with stationary limit switches present, however, the relay and hence the motor 42 would be reversed by one of the stationary switches and thereafter would be controlled by the movable switches in the normal manner. This switch arrangement, then, eliminates any need for the operator to reset the mechanism (electrically or mechanically) at the end of a winding cycle or on the occasion of an interrupted cycle.

It is believed to be clear that applicant has provided an improved windup apparatus in accordance with the objects of this invention.

Although a single preferred embodiment has been described in detail in accordance with the Patent Statute, many variations and modifications within the spirit of the invention will occur to those skilled in the art, and all such are considered to fall within the scope of the following claims.

What is claimed is:

1. An improved high speed windup apparatus for forming tapered yarn packages, said apparatus comprising in combination, a support structure, a drive roll member rotatably mounted on said structure, a windup chuck member for maintaining a bobbin mounted thereon in operative friction drive contact with said drive roll member, a movable means cooperating with said structure and said windup chuck member for mounting said windup chuck for movement between a first position in operative driving engagement with said drive roll member and a second position spaced a given distance from said drive roll member to accommodate a yarn package forming on a bobbin on said chuck member, a yarn traverse guide means mounted on said structure in cooperation with said drive roll member and a bobbin on said chuck member and operative to traverse a running yarn line on a bobbin to build a yarn package thereon, a drive means mounted on said structure and cooperating with said traverse guide means to move said traverse guide means along a yarn traversing path adjacent and in alignment with said members, and a control means on said structure cooperating with said traverse guide means, said movable means, and said drive means to automatically control the length of movement of said traverse guide means along said path in response to the distance between said chuck member and said Windup roll member and to control the direction of movement of said traverse guide means according to the position of said traverse guide means along said path so that a running yarn line engaging said traverse guide means and drive roll is formed into a tapered yarn package on a bobbin mounted on said chuck member during operation of the apparatus, said control means comprising two spaced electrical switch units, said units each electrically operatively connected to energize said drive means and mounted for relative movement toward and away from each other, said control means further comprising a first actuating means cooperating with said movable means and at least one of said switch units for varying the spacing between said switch units in response to changes in the distance between said chuck member and said drive roll member, said control means further comprising a second actuating means cooperating with said switch units to alternately actuate the same to reverse the direction of movement of said drive means in response to the position of said yarn traverse guide means.

2. The improved apparatus of claim 1 in which said second actuating means comprises a constant speed reciprocating member positioned, constructed and arranged to reciprocate in accordance with said traverse guide means and alternately actuate said switch units to reverse said drive means when said traverse guide approaches the desired limit of the yarn package being wound on a bobbin on said chuck member.

3. The improved apparatus of claim 2 in which said second actuating means is carried by said yarn traverse guide means, said switch elements lying on a line in parallel alignment with said path of movement of said traverse guide means.

References Cited UNITED STATES PATENTS 2,265,036 12/1941 Gift 242-43.1 2,830,774 4/1958 Guibert 242-43 FOREIGN PATENTS 514,499 10/1952 Belgium.

560,657 4/ 1944 Great Britain.

567,673 2/ 1945 Great Britain.

607,487 8/ 1960 Italy.

STANLEY N. GILREATH, Primary Examiner. 

1. AN IMPROVED HIGH SPEED WINDUP APPARATUS FOR FORMING TAPERED YARN PACKAGES, SAID APPARATUS COMPRISING IN COMBINATION, A SUPPORT STRUCTURE, A DRIVE ROLL MEMBER ROTATABLY MOUNTED ON SAID STRUCTURE, A WINDUP CHUCK MEMBER FOR MAINTAINING A BOBBIN MOUNTED THEREON IN OPERATIVE FRICTION DRIVE CONTACT WITH SAID DRIVE ROLL MEMBER, A MOVABLE MEANS COOPERATING WITH SAID STRUCTURE AND SAID WINDUP CHUCK MEMBER FOR MOUNTING SAID WINDUP CHUCK FOR MOVEMENT BETWEEN A FIRST POSITION IN OPERATIVE DRIVING ENGAGEMENT WITH SAID DRIVE ROLL MEMBER AND A SECOND POSITION SPACED A GIVEN DISTANCE FROM SAID DRIVE ROLL MEMBER TO ACCOMMODATE A YARN PACKAGE FORMING ON A BOBBIN ON SAID CHUCK MEMBER, A YARN TRAVERSE GUIDE MEANS MOUNTED ON SAID STRUCTURE IN COOPERATION WITH SAID DRIVE ROLL MEMBER AND A BOBBIN ON SAID CHUCK MEMBER AND OPERATIVE TO TRAVERSE A RUNNING YARN LINE ON A BOBBIN TO BUILD A YARN PACKAGE THEREON, A DRIVE MEANS MOUNTED ON SAID STRUCTURE AND COOPERATING WITH SAID TRAVERSE GUIDE MEANS TO MOVE SAID TRAVERSE GUIDE MEANS ALONG A YARN TRAVERSING PATH ADJACENT AND IN ALIGNMENT WITH SAID MEMBERS, AND A CONTROL MEANS ON SAID STRUCTURE COOPERATING WITH SAID TRAVERSE GUIDE MEANS, SAID MOVABLE MEANS, AND SAID DRIVE MEANS TO AUTOMATICALLY CONTROL THE LENGTH OF MOVEMENT OF SAID TRAVERSE GUIDE MEANS ALONG SAID PATH IN RESPONSE TO THE DISTANCE BETWEEN SAID CHUCK MEMBER AND SAID WINDUP ROLL MEMBER AND TO CONTROL THE DIRECTION OF MOVEMENT OF SAID TRAVERSE GUIDE MEANS ACCORDING TO THE POSITIN OF SAID TRAVERSE GUIDE MEANS ALONG SAID PATH SO THAT A RUNNING YARN LINE ENGAGING SAID TRAVERSE GUIDE MEANS AND DRIVE ROLL IS FORMED INTO A TAPERED YARN PACKAGE ON A BOBBIN MOUNTED ON SAID CHUCK MEMBER DURING OPERATION OF THE APPARATUS, SAID CONTROL MEANS COMPRISING TWO SPACED ELECTRICAL SWITCH UNITS, SAID UNITS EACH ELECTRICALLY OPERATIVELY CONNECTED TO ENERGIZE SAID DRIVE MEANS AND MOUNTED FOR RELATIVE MOVEMENT TOWARD AND AWAY FROM EACH OTHER, SAID CONTROL MEANS FURTHER COMPRISING A FIRST ACTUATING MEANS COOPERATING WITH SAID MOVABLE MEANS AND AT LEAST ONE OF SAID SWITCH UNITS FOR VARYING THE SPACING BETWEEN SAID SWITCH UNITS IN RESPONSE TO CHANGES IN THE DISTANCE BETWEEN SAID CHUCK MEMBER AND SAID DRIVE ROLL MEMBER, SAID CONTROL MEANS FURTHER COMPRISING A SECOND ACTUATING MEANS COOPERATING WITH SAID SWITCH UNITS TO ALTERNATELY ACTUATE THE SAME TO REVERSE THE DIRECTION OF MOVEMENT OF SAID DRIVE MEANS IN RESPONSE TO THE POSITION OF SAID YARN TRAVERSE GUIDE MEANS. 